(BQ) Part 2 book "Pathology of the maxillofacial bones - A guide to diagnosis" presentation of content: Fibro-Osseous lesions, giant cell lesions, bone tumors, other lesions involving the maxillofacial skeleton, diseases of the temporomandibular joint. | 7 Fibro-Osseous Lesions Introduction The current classification of maxillofacial fibroosseous lesions includes fibrous dysplasia, ossifying fibroma and osseous dysplasia [1, 2]. In previous classifications, efforts to discern between bone and cementum caused designations as cement-ossifying of cementifying fibroma or cemental dysplasia. However, none of the proposed differences between cementum and bone has withstood the test of time and therefore terms as cementifying or cemental have been dropped as unwanted and confusing [3]. All lesions to be discussed under the heading fibro-osseous are composed of bone and fibrous tissue. Sutural tissue that connects the several bones that make up the craniofacial skeleton is composed of the same two elements and may be a diagnostic pitfall if not recognized as a normal component of this anatomical area (Figs. and ) Fibrous Dysplasia Fibrous dysplasia is composed of cellular fibrous tissue containing trabeculae mainly consisting of woven bone. It occurs in three clinical subtypes: monostotic which affects one bone, polyostotic which affects multiple bones, and Albright’s syndrome in which multiple bone lesions are accompanied by skin hyperpigmentation and endocrine disturbances [1]. Activating missense mutations of the gene encoding the α subunit of the stimulatory G protein are a consistent finding in the various forms of fibrous dysplasia [4]. Craniofacial fibrous dysplasia usually is of the monostotic type [5]. Mostly, the disease occurs during the first three decades although occasionally, cases are seen at an older age. The maxilla is more often involved than the mandible [1]. Usually, fibrous dysplasia clinically presents itself as a painless swelling of the involved bone. Radiographically, the classical appearance is described as orange-skin or ground-glass radiopacity without defined borders [1]. In the maxilla, fibrous dysplasia may extend by continuity across suture lines to involve adjacent bones which is a
